Create Setup_SD_Script

* A script to partition/format an SD card, and extract the lasted Arch Linux ARM build to it.
 * Works on the Raspberry Pi and Raspberry Pi 2.

## Summary:
 * This script installs the latest version of Arch Linux ARM to an SD card. 
 * Based on the official installation recommendations: https://archlinuxarm.org/platforms/armv6/raspberry-pi#installation 

## Input:
### This script requires the following input:
 1. The full path to a block device where Arch ARM is to be installed.

### This script performs the following actions:
 1. Creates 100MB vfat (boot) partition on specified block device;
 2. Creates ext4 (root) parition on remaining space;
 3. Creates a temporary directory for mount points and download;
 4. Downloads a tarball of the lastest ArchARM distribution;
 5. Extracts files to new root partition;
 6. Moves /boot directory to boot partiton.

## Usage: 
`bash flash-sdcard.sh /dev/sdcard`

## Source Tarball Download: 
### The `$SRC` variable is set to the url of the source tarball for the desired version of Arch Linux ARM: 
 * Raspberry Pi (Original/Model A, B, B+): http://archlinuxarm.org/os/ArchLinuxARM-rpi-latest.tar.gz
 * Raspberry Pi 2: http://archlinuxarm.org/os/ArchLinuxARM-rpi-2-latest.tar.gz

Setup_SD_Script

@@ -0,0 +1,106 @@
+# Automated Arch Linux ARM install script
+
+#!/bin/sh
+# flash-sdcard.sh
+#
+# Automated Arch Linux ARM install script
+# This script installs the latest version of Arch Linux ARM to an SD card.
+#
+# Based on official installation recommendations: 
+#   https://archlinuxarm.org/platforms/armv6/raspberry-pi#installation
+#
+# This script requires the following input:
+#   1. The full path to a block device where Arch ARM is to be installed.
+#
+# This script performs the following actions:
+#   1. Creates 100MB vfat (boot) partition on specified block device;
+#   2. Creates ext4 (root) parition on remaining space;
+#   3. Creates a temporary directory for mount points and download;
+#   4. Downloads a tarball of the lastest ArchARM distribution;
+#   5. Extracts files to new root partition;
+#   6. Moves /boot directory to boot partiton.
+#
+# Usage: 
+#   bash flash-sdcard.sh /dev/sdcard
+# 
+
+## Set flags
+set -u
+#set -e    # fdisk may throw error codes even on successful writes.
+
+## Check if input value was given and exists.
+## Show usage message if not.
+if [ $# -ne 1 ] || [ ! -e $1 ]; then
+    echo
+    echo "Valid path to SD card device is a required argument."
+    echo
+    echo "Example:"
+    echo "   bash $0 /dev/mmcblk0"
+    echo
+    exit 1
+fi
+
+## Wipe SD card.
+#dd if=/dev/zero of=$1
+
+## Create partitions using fdisk by simulating user input.
+## (fdisk was not designed with non-interactive use in mind.)
+echo "o
+n
+p
+1
+
++100M
+n
+p
+2
+ 
+ 
+p
+w
+q
+" | fdisk $1
+
+## Sync changes and update partition table.
+sync; partprobe $1; sync
+
+## Create tempory directory for mounts and download.
+cd `mktemp -d`
+mkdir boot root
+
+## If partition numbering for the device follows sda -> sda1 format.
+if [ -e "$1"1 ]; then
+  mkfs.vfat "$1"1
+  mount "$1"1 boot
+  mkfs.ext4 "$1"2
+  mount "$1"2 root
+
+## If partition numbering for the device follows mmcblk0 -> mmcblk0p1 format.
+else
+  mkfs.vfat "$1"p1
+  mount "$1"p1 boot
+  mkfs.ext4 "$1"p2
+  mount "$1"p2 root
+fi
+
+## Download tarball 
+SRC="http://archlinuxarm.org/os/ArchLinuxARM-rpi-latest.tar.gz" #RasPi
+#SRC="http://archlinuxarm.org/os/ArchLinuxARM-rpi-2-latest.tar.gz" #RasPi 2
+wget $SRC
+
+## Download and verify PGP signature
+## (Best practice, but disabled for simplicity's sake.)
+#wget "$SRC".sig
+#gpg --recv-keys 2BDBE6A6
+#gpg --verify $SRC
+
+## Extract tarball
+tar -xf ArchLinuxARM-rpi-latest.tar.gz -C root 
+sync
+mv root/boot/* boot   # Move /boot files to boot partition
+sync
+
+## Unmount mounts
+umount boot root
+
+## We're done.